Evaluation of association of impairment of attention with other symptoms of delirium :Sandeep Grover, Aseem Mehra, Subho Chakrabarti, Swapnajeet Sahoo, Ajit Avasthi, Journal of Mental Health and Human Behaviour

ORIGINAL ARTICLE
Year : 2021 | Volume : 26 | Issue : 1 | Page : 54--61

Evaluation of association of impairment of attention with other symptoms of delirium

Sandeep Grover, Aseem Mehra, Subho Chakrabarti, Swapnajeet Sahoo, Ajit Avasthi
Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Chandigarh, Punjab, India

Correspondence Address:
Sandeep Grover
Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Chandigarh - 160 012, Punjab
India

Abstract

Aim: To evaluate the association of impairment of attention with other symptoms of delirium. Methodology: Eighty-six patients with delirium as per the Diagnostic and Statistical Manual, 5^th Revision seen in the consultation-liaison psychiatry setup of a tertiary care hospital were cross-sectionally assessed on the short informant questionnaire on cognitive decline in the elderly (Retrospective), montreal cognitive assessment (MoCA), and delirium rating scale revised-98 (DRS-R98) version. Results: The mean age of the study participants was 46.6 (standard deviation [SD] – 16.4) years. All the patients had impairment in attention with the altered sleepwake cycle, acute onset of illness, with the fluctuating course and underlying physical disease. In terms of severity, the severity score was the highest for the item of sleep-wake cycle disturbances, followed by motor agitation. The mean noncognitive symptoms domain of the DRS-R98 domain were more than the mean score of the cognitive symptom domain of DRS-R98. The mean total score on MoCA was 11.9 (SD: 7.5). Higher attention impairment was associated with more severe noncognitive and cognitive symptoms and higher delirium severity as assessed by DRS-R98. Higher severity of attention deficit was also associated with higher impairment in other domains of cognition of MoCA. Cognitive symptoms, as evaluated by DRS-R98, had more significant correlations with various domains of MoCA except for language and abstraction. Conclusion: Attention deficits are the core symptom of delirium and have a significant impact on other cognitive and noncognitive symptoms of delirium.

How to cite this article:
Grover S, Mehra A, Chakrabarti S, Sahoo S, Avasthi A. Evaluation of association of impairment of attention with other symptoms of delirium.J Mental Health Hum Behav 2021;26:54-61

How to cite this URL:
Grover S, Mehra A, Chakrabarti S, Sahoo S, Avasthi A. Evaluation of association of impairment of attention with other symptoms of delirium. J Mental Health Hum Behav [serial online] 2021 [cited 2023 Jun 4 ];26:54-61
Available from: https://www.jmhhb.org/text.asp?2021/26/1/54/322825

Full Text

Introduction

Delirium is an acute medical emergency, which is highly prevalent in the inpatient treatment setting. It is often associated with adverse outcomes in the form of longer duration of hospital stay, mortality, and treatment cost.[1] Delirium is also known to be a risk for developing cognitive deficits and dementia.[2] Although disturbance in attention is considered to be the core symptom of delirium, the symptom clusters of delirium are broadly divided into two categories, i.e., cognitive and noncognitive symptoms. Although many studies have evaluated the symptom profile of delirium, a few attempts have been made to study the associations of cognitive and noncognitive symptoms.[3],[4],[5],[6],[7]

Diagnostic and Statistical Manual, 5th Revision (DSM-5), lays more emphasis on the cognitive symptoms. It lists disturbance in the attention and awareness, along with an additional disturbance in cognition (e.g., memory deficit, disorientation, language, visuospatial ability, or perception) among the diagnostic criteria with no mention of noncognitive symptoms, i.e., sleeps disturbances, delusions, hallucinations, motoric disturbances, and thought process abnormalities. However, studies which have evaluated the prevalence of noncognitive symptoms in patients with delirium suggest that some of these symptoms are also highly prevalent in patients with delirium.[3],[4],[7],[8],[9],[10] Some of the studies indicated that noncognitive features dominate the clinical picture during the early stages of delirium, while cognitive impairments peak after 1 week and dominate the clinical picture after that.[4] In this study, noncognitive symptoms (e.g., perceptual disturbances, sleep-wake cycle disturbances, lability of mood, and presence physical disorder) showed lower correlations with the mini-mental status scale scores.[4] However, other studies which have evaluated the association of cognitive and noncognitive symptoms suggest that there is an association of severity of attention as assessed by using the cognitive test for delirium (CTD) with higher severity of delirium, as assessed by delirium rating scale-revised 98 (DRS-R98) version.[3] In this study, a higher level of attention deficits was associated with higher dysfunction on all other domains of cognition on CTD. There was a significant correlation between higher severity of cognitive functions as assessed on CTD and severity of delirium as measured by the total DRS-R-98 score and the DRS-R-98 severity score.[3]

Another study from India examined the association of cognitive functions as assessed by Hindi Mental Status Examination (HMSE) with noncognitive symptoms as assessed using DRS-R-98 and showed that higher level of cognitive deficits as assessed by HMSE were associated with higher severity of delirium as indicated by higher DRS-R-98 total score, DRS-R-98 severity score, DRS-R-98 cognitive subscale score, DRS-R-98 noncognitive domain subscale score, and DRS-R98 severity score without attention score. When the association of each item of DRS-R-98 and HMSE was evaluated, except for the items of delusions, lability of affect and motor retardation, higher severity of cognitive symptoms as assessed on HMSE were associated with higher severity of all the cognitive symptoms and most of the noncognitive symptoms as assessed by DRS-R-98.[4] However, it is essential to note that these scales do not evaluate all the cognitive domains. Hence, there is a need to understand the association between cognitive and noncognitive symptoms of delirium by using a broader scale, which covers cognitive symptoms more comprehensively.

The commonly used scales for assessing cognitive functions in patients with delirium include Mini-Mental State Examination (MMSE), CTD and the cognitive subscale of delirium DRS-R98 and HMSE. However, very few previous studies have used the Montreal Cognitive Assessment (MoCA) in patients with delirium to assess the cognitive symptoms of delirium.[11],[12] A previous study used MMSE, Mini-Cog, clock drawing test, and MoCA to assess delirium in 52 patients waiting for arthroplasty. In the postoperative phase, six patients developed delirium. Of these, MMSE and Mini-Cog could be helpful in recognizing 3 out of 6 patients with delirium, whereas MoCA was useful in identifying all the 6 patients with delirium.[11]

MoCA assesses attention and concentration, executive functions, memory, language, visuo-constructional skills, conceptual thinking, calculations, and orientation. MoCA is considered to have better sensitivity, specificity, positive and negative predictive value than other instruments like HMSE, MMSE or CDT in picking up cognitive deficits.[13] MoCA uses digit span (both forward and backward), 100 minus seven, and vigilance span to assess attention. In addition, MoCA also uses alternating trail making also, which also assess one of the components of attention, in addition to the executive functions. In doing so, MoCA assesses the ability to focus and sustain attention.[14] In contrast, HMSE relies on the backward repetition of the word 'WORLD” only.[15] DRS-R98 lists digit span as the example for the assessment of attention. In addition, it also suggests using the WORLD backward, counting in reverse from 72 to 59, reporting days of weeks backward starting with Saturday, 100-7, and vigilance span for assessing attention. However, it is important to note that for DRS-R98, for rating the items, the clinicians do not have to rely on testing only, and can also take account of last 24 h into account.[16] CTD depends on visual attention span (patients are shown the pictures and later asked to recognize the same) and vigilance test by using the items of letter cancellation test.[17] Accordingly, it can be said that MoCA relies upon a broader objective assessment of attention. Hence, assessing the cognitive functions of patients with delirium by using MoCA and evaluating their relationship with noncognitive symptoms can help in understanding the relationship of both sets of symptoms in a better way. In this background, the present study aims to assess the association of impairment of attention with other symptoms of delirium.

Methodology

The present study was conducted in the consultation-liaison psychiatry (CLP) setup of a tertiary care hospital, in which there is a lot of cross-referrals across different specialities. This study was conducted after seeking approval from the Institutional Ethics Committee. The study followed the ethical recommendations as per the declaration of Helsinki and proxy written informed consent was obtained from the family caregivers who were staying with patients during the inpatient stay. All the consecutive patients referred to CLP services during the study period and diagnosed with delirium were eligible for this study. To be included in the study, the participants were required to be aged ≥18 years and meet the diagnostic criteria for delirium as per the DSM-5. Those patients who were on psychotropics before the assessment, had substance-related delirium, sensory deprivation (loss of vision and hearing impairment), aphasia, and axis-I psychiatric disorders, and delirium-related alcohol withdrawal were excluded. Similarly, those with preexisting cognitive deficits were also excluded. The presence of preexisting cognitive deficits was ruled out on the basis of scores on the Short Informant Questionnaire on Cognitive Decline in the Elderly (Retrospective IQCODE).[18] Patients admitted to intensive care units and on mechanical ventilation were also excluded from the study.

The study participants were evaluated on short IQCODE, MoCA, and DRS-R98 version.

Instruments

Delirium rating scale–revised-98

This is one of the most widely used scales to assess the severity and symptom profile of delirium. The scale has 16 items, 13 of which evaluate the symptoms of delirium and 3 items of the scale are considered to be diagnostic items. The severity items are further divided into cognitive (items 9–13) and noncognitive symptoms (items 1–8) of delirium. Each of the severity items is rated on a 4-point scale (0–3), and the total severity score ranges from 0 to 39. Two of the three diagnostic items are also rated on a 4-point scale, and 1 item is rated on a 3-point scale (0–2). It has been shown to have high inter-rater reliability, sensitivity, and specificity.[16],[19]

Montreal cognitive assessment

It is a brief 30-question test that takes around 10–12 min to complete and assesses cognitive functions. The cognitive domains assessed by using MoCA include attention and concentration, executive functions, memory, language, visuo-constructional skills, conceptual thinking, calculations, and orientation. The total score ranges from 0 to 30, and a total score of ≥26 is considered normal. The score ranging from 18 to 25 is considered to be an indicator of mild cognitive impairment. To counterbalance the effect of lower education, 1 point is added to the final score of those individuals with <12 years of education.[20]

Short informant questionnaire on cognitive decline in the elderly (Retrospective)

This is a 16-item instrument which is based on the input provided by a key relative to determine the cognitive status of the person for the specified period (6 months for this study). Each item is rated on a 5-point scale (0 to 5) with score 3, indicating no change and scores higher than 3, indicating a decline in cognitive functioning and lower scores suggests an improvement in cognitive functions. To obtain the final score, the score obtained for all items is added and divided by 16. A mean score of >3.6 is considered to be an indicator of cognitive decline. The coefficient alpha for the scale has been found to be very high, ranging from 0.93 to 0.97. The sensitivity and specificity of the scale vary from 69%–80% and 80%–83%, respectively, among various studies.[18],[21] In the current study, we excluded those patients with a cutoff score of >3.60, as used in the previous studies.

The caregivers of the patients diagnosed with delirium by the CLP team were approached and they were explained about the purpose and procedure of the study. Patients whose caregivers provided written informed consent for the study were interviewed in detailed to confirm the diagnosis of delirium as per the DSM-5 criteria and to rule out other psychiatric disorders. Then, the patients were assessed on the short-IQCODE to rule out the preexisting cognitive impairment. All the evaluation was done over a period of 30–45 min. Finally, patients with delirium, without preexisting cognitive deficits were included in the study and were evaluated on DRS-R-98 and MoCA.

Statistical analyses

Data were analyzed using the Statistical Package for the Social Sciences, Sixteenth version (SPSS-16) (SPSS Inc. Released 2007. SPSS for Windows, Version 16.0. SPSS Inc., Chicago). For descriptive purposes, mean and standard deviation (SD) were estimated for the continuous variables. For the categorical variables, frequency and percentages were computed. Associations of cognitive functions with noncognitive functions were studied by using Pearson's product-moment correlation and Spearman rank correlation. In view of the multiple correlations, a P value of 0.003 (0.05/18) was considered statistically significant.

Results

One hundred and four (n = 104) consecutive patients diagnosed with delirium by the CLP team were approached for the study, of whom 86 fulfilled the selection criteria and formed the study sample.

The mean age of the study participants was 46.6 (SD-16.4) years. About one-third (N = 27; 31.4%) of the participants were aged 60 years or more. Majority of the participants were male (N = 64; 74.4%), and the mean duration of delirium at the time of assessment was 1.8 (SD-1.1) days. In terms of the symptom profile, all the patients had impairment in attention. In addition, all the patients exhibited sleep-wake cycle disturbances, had acute onset of illness, with the fluctuating course and underlying physical disease [Table 1]. In terms of severity, the mean severity score was the highest for the item of sleep-wake cycle disturbances, followed by motor agitation [Table 1]. The mean noncognitive symptoms domain score was more than the mean score of the cognitive symptom domain [Table 1]. In terms of MoCA, the mean total score was 11.9 (SD: 7.5) [Table 1].{Table 1}

Impaired attention is understood as the core symptom of delirium. Hence, based on the severity of the attention domain of the MoCA, the study sample was divided into three groups. Group I included participants who scored 0–2, Group II and Group III included participants with a score of 3–4 and 5–6, respectively, on the attention domain of MoCA. It was seen that higher impairment in attention was associated with more severe noncognitive and cognitive symptoms as assessed by DRS-R98. Higher severity of attention impairment was also associated with more severe-cognitive, cognitive symptoms, the overall severity of delirium as assessed by mean severity and total DRS-R98 scores [Table 2]. Similarly, on MoCA too, higher severity of attention-deficit was associated with higher impairment in other cognition domains [Table 2].{Table 2}

Association of cognitive functions with noncognitive symptoms of delirium

When the association of all the domains of the MoCA and DRS-R98 was assessed, it was seen that the cognitive symptoms as evaluated by DRS-R98 had more significant correlations with various domains of MoCA [Table 3]. Among the cognitive domains of MoCA, language and abstraction had no significant correlation with both cognitive and noncognitive domains of DRS-R98. Among the DRS-R98 noncognitive items, language and thought process abnormality had a correlation with all the cognitive domains of MoCA, except for language and abstraction [Table 3].{Table 3}

Discussion

The present study included 86 patients with delirium to assess the association between cognitive and noncognitive symptoms of delirium. We excluded patients with preexisting cognitive deficits on the basis of IQCODE and also excluded patients with alcohol withdrawal-related delirium. These were done to minimize the impact of preexisting cognitive deficits on symptom profile, as some of the studies suggest that there are subtle differences in the symptom profile of delirium in patients with and without dementia/cognitive deficits.[22],[23] Similarly, it is well-known that prolong intake of alcohol can have a negative impact on the cognition.[24] Accordingly, it can be said that the associations seen between the cognitive and noncognitive symptoms were not influenced by the preexisting cognitive deficits.

The symptom profile of delirium as assessed on DRS-R98 in the present study is comparable to the previous studies from India, which has evaluated patients in the CLP setting.[25],[26],[27],[28],[29] The MoCA score obtained in the present study is slightly lower than the previous study,[11],[12],[30] which possibly suggest that in the present study, patients had more severe cognitive symptoms. When we divided the study sample based on the attention scores on MoCA into three groups (0–2, 3–4, and 5–6), it was seen that those with higher severity of delirium had higher symptom severity of other symptoms of delirium, which was more evident for cognitive symptoms as assessed on DRS-R98 and also for cognitive functions as assessed on MoCA too. In terms of noncognitive symptoms as assessed on DRS-R98, the significant impact of attention was seen on all the symptoms except for delusions. These findings support the notion that attention is the core symptom of delirium, as reported in previous studies which evaluated attention by using CTD and HMSE.[3],[4],[31] However, findings of the present study are not in line with an earlier study from India, which used CTD.[3] In the correlation analysis, when the association of attention deficits with various items of DRS-R98 was evaluated in the present study, it correlated significantly with all the items except for sleep-wake cycle disturbances, delusions, lability of affect, motor agitation, and motor retardation. Previous studies have also reported similar associations.

In the correlation analysis, when the association of various other domains of cognitive functions as assessed by MoCA and MoCA total score with various items of DRS-R98 was evaluated in the present study, other cognitive domains (except for language and abstraction) correlated significantly with various domains of cognitive functions assessed by DRS-R98. In terms of noncognitive symptoms, language, and thought process, abnormality had a correlation with various cognitive domains (except for language and abstraction) as assessed by MoCA. Delusions, lability of affect, and motoric symptoms did not correlate with any of the other domains of cognition as assessed by MoCA. These findings suggest that compared to attention deficits, other cognitive symptoms are not as closely associated with noncognitive symptoms. Previous studies have also suggested similar associations.[4],[7]

Our study has limitations, which must be kept in mind while interpreting the findings of the present study. This was a cross-sectional study which included patients evaluated in the CLP setting, who may be having heterogeneous etiologies associated with delirium. The study included few older patients, who are actually more prone to delirium. Hence, the findings of the present study may not be generalizable to the elderly population. Attempts must be made in future studies to overcome these limitations.

Conclusion

The present study provides objective evidence that attention deficits are the core symptom of delirium and have a significant impact on other cognitive and noncognitive symptoms of delirium. The study also suggests that MoCA may be useful in assessing in cognitive functioning in patients with delirium.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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